1. Field of the Invention
The invention relates to a device for guiding portions of backwater produced or stored at different levels of a paper machine. The device includes an upper backwater chamber for the backwater being produced higher up and a lower backwater chamber arranged farther below into which the backwater from the upper backwater chamber can flow.
2. Discussion of Background Information
In the operation of a paper machine, the water from the paper suspension is either thrown off through the wires in the paper machine or scraped off with the aid of foils. This water, i.e., the backwater, is produced in large amounts in a small space. Devices of the type discussed here are appropriate for removing the backwater from the vicinity of the paper machine. In many paper machines, various partial flows of the backwater must be brought together from various geodetic heights for re-use. In this connection, vertical flows (waterfalls) may form. They have the disadvantage that they entrain and incorporate parts of the surrounding air.
It is not always simple to manage with the space available for this purpose in a paper machine because, due to the large amount of water, it is necessary to keep the flow cross sections for such backwater flows wide and favorable to flowing. Therefore, enough space is seldom available for removing the backwater without vertical flows.
The present invention provides a device with which it is possible to bring together parts of the backwater from various geodetic heights in a space-saving manner and with as little entrainment of air as possible. Fluctuations in the amount of water should be problem-free as well.
In particular, the present invention provides a device similar to that discussed above, but in which the upper backwater chamber is connected to the lower backwater chamber via several hydraulic lines having inlet openings inside the upper backwater chamber. Further, these inlet openings are arranged at different geodetic heights relative to one another.
With the aid of the device according to the invention, the differences in height can be overcome with extremely little entrainment of air. The predominant part of the backwater can flow off downwardly through lines that are completely filled with water. The inlet openings lie at different heights such that, in general, just one single line will be only partially filled with backwater, whereas the inlet openings of the others are located either completely below or above the water level. The number of hydraulic lines with water flowing through them will differ, depending on the water level in the upper backwater chamber.
The present invention is directed to an apparatus for guiding portions of backwater produced or stored at different levels of a machine. The apparatus includes an upper backwater chamber arranged to receive first backwater, a lower backwater chamber arranged below the upper backwater chamber and to receive at least a portion of the first backwater from the upper backwater chamber. A plurality of hydraulic lines are arranged to couple the upper backwater chamber to the lower backwater chamber, and inlet openings of the plurality of hydraulic lines are arranged inside the upper backwater chamber and are arranged at different geodetic heights relative to one another.
In accordance with a feature of the instant invention, the lower backwater chamber can be further arranged to receive a second backwater, and the first backwater can be produced higher up in the machine than the second backwater.
According to another feature of the invention, the upper backwater chamber can include an inclined floor, and the inlet openings may be coupled to the inclined floor. An angle of the inclined floor to horizontal may be between about 30xc2x0 and 60xc2x0.
In accordance with still another feature of the present invention, at least some of inlet openings may lie above a floor of upper backwater chamber.
An hydraulic line coupled to a lowermost inlet opening can have a free cross-sectional area that is at least three times as large as a remainder of the plurality of hydraulic lines. The remainder of the hydraulic lines can have a free cross-section of between about 100 and 300 cm2.
According to a further feature of the present invention, the plurality of hydraulic lines can be round. Additionally, or alternatively, the plurality of hydraulic lines can be annular lines arranged concentrically to one another.
In accordance with still another feature of the instant invention, the plurality of hydraulic lines can be arranged to terminate below a backwater level in the lower backwater chamber.
The lower backwater chamber may be coupled to a fluid guiding element arranged to receive a portion of second backwater produced at a lower level than the first backwater. The fluid guiding element is a channel.
Further, the lower backwater chamber can be coupled to a downstream backwater tank, relative to a backwater flow direction.
The inlet openings may be arranged such that a lowest point of one inlet opening is at a same level as a highest point of an adjacent inlet opening.
Moreover, according to the instant invention, a level of the backwater in the upper backwater chamber may partially fills one of the inlet openings.
A weir and an overflow drain can be provided. The weir may control a maximum backwater level in the upper backwater chamber.
The inlet openings can be obliquely angled relative to the plurality of hydraulic lines. A portion of a bottom of the upper backwater chamber may be angled relative to horizontal, and the angle of the bottom may correspond to the oblique angle of the inlet openings. The inlet openings can be arranged such that a lowest point of one inlet opening is at a same level as a highest point of an adjacent inlet opening. Further, a lowermost inlet opening arranged at an end of the bottom. Additionally, or alternatively, the hydraulic lines can be concentrically arranged. A lowermost inlet opening can be arranged at a lowermost point of the upper backwater chamber.
In accordance with still another feature of the present invention, the machine can be a paper machine.
The present invention is directed to a process of guiding backwater produced or stored at different levels in a machine. The process includes collecting first backwater in an upper backwater chamber, and guiding the first backwater from the upper backwater chamber to a lower backwater chamber through inlet openings to a plurality of hydraulic lines. The inlet openings are arranged at different geodetic heights relative to one another.
According to a feature of the present invention, a level of the first backwater in the upper backwater chamber is such that one of the inlet openings can be partially filled with the first backwater.
The process can further include guiding the first backwater into the lower backwater chamber at a level below a second backwater level contained in the lower backwater chamber.
The first backwater may be guided through concentrically arranged hydraulic tubes.
In accordance with still yet another feature of the instant invention, a first backwater level can controlled by a weir and an overflow drain.
Other exemplary embodiments and advantages of the present invention may be ascertained by reviewing the present disclosure and the accompanying drawing.